If you haven’t already downloaded latest version of GNS3 i.e GNS3 7.0.2 , grab it now. New release includes mouthful of features & bug fixes .Most interesting feature is the addition of Qemu Image of Microcore Linux 2.10 which will help you simulate PCs/Workstations/Computers right within GNS3 interface. Support for SSH, iptables, iproute , tcpdump , IPv6 has been included to test connectivity & routing features. Also, we are awaiting Release of next version of dynamips (Dynamips version > 0.2.8 RC2) , which will incorporate some more features into the current GNS3 build.